1. Field of the Invention
The present invention relates to a method for exposing photoresist film of semiconductor device, and in particular to an improved method for exposing photoresist film of semiconductor device wherein a wafer is sequentially shifted by a predetermined distance so that the exposed regions before and after each shift have an overlapping region having an area larger than or equal to that of the die pattern to prevent defects on the exposure mask from being transcribed to the photoresist film.
2. Description of the Background Art
An exposure process refers to a process for transcribing a predetermined pattern on an exposure mask to a wafer using an exposure apparatus.
Generally, a method for manufacturing an exposure mask is as follows.
A light shielding material such as chrome is deposited on a quartz substrate. Thereafter, a photoresist film reactive to electron beam is coated on the light shielding material.
Next, the photoresist film is exposed to an electron beam using an electron beam exposure apparatus including a desired pattern to be formed on a semiconductor wafer programmed therein and then developed to form a photoresist film pattern.
Thereafter, the light shielding material is etched using the photoresist film pattern as an etching mask. The photoresist film pattern is then removed to form an exposure mask including a light shielding pattern.
However, as the size of the pattern is decreased, defects are generated.
FIGS. 1a and 1b are plane views illustrating exposure mask including line patterns designed therein.
Referring to FIGS. 1a and 1b, exposure masks of FIGS. 1a and 1b comprise line type light shielding patterns 13 and 23 disposed on quartz substrates 11 and 21. Defects 15 and 25 are generated during a formation process of the light shielding patterns.
When an exposure and development process is performed using the exposure mask having defects therein, the defects are also transcribed to the semiconductor wafer.
As described above, in accordance with the conventional exposure method, defects on the exposure mask are transcribed to a thin film to be etched on the semiconductor wafer. Therefore, defective exposure mask cannot be used and must be discarded in order to prevent the defects from being transcribed to the semiconductor wafer, which lowers the productivities of exposure masks and also semiconductor devices.